Synthesis of carbonates from CO
<sub>2</sub>
and epoxides catalyzed by the system of
<i>N</i>
‐heterocyclic carbene, hydrogen bond donor, CrCl
<sub>2</sub>
, and tetrabutylammonium bromide
作者:Kuikui Zhang、Zhenbang Liu、Ning Liu
DOI:10.1002/aoc.6347
日期:2021.10
pyrazole nitrogen bearing benzimidazolium salts was employed as hydrogenbond donor, TBAB was used as nucleophilic reagent, respectively. Under mild conditions (50°C and 1 bar CO2), the terminal epoxides displayed high reactivity in the three-component catalytic system. The catalytic system showed also high catalytic activity for the internal epoxides by increasing the temperature and CO2 pressure and/or
开发了包括吡啶桥联苯并咪唑鎓盐、CrCl 2和四丁基溴化铵(TBAB)的三组分催化体系。基于对照实验和光谱测量,阐明了三种组分在催化过程中的作用,其中苯并咪唑盐用作N-杂环卡宾前体,一种由 CrCl 2与吡啶氮配位生成的新 Cr 配合物和分别采用含吡唑氮的苯并咪唑盐作为氢键供体,TBAB作为亲核试剂。在温和条件下(50°C 和 1 bar CO 2),末端环氧化物在三组分催化体系中表现出高反应性。通过提高温度和CO 2压力和/或延长反应时间,催化体系对内环氧化物也显示出高催化活性。
A Metal‐Free Synthesis of N‐Aryl Carbamates under Ambient Conditions
作者:Wusheng Guo、Joan Gónzalez‐Fabra、Nuno A. G. Bandeira、Carles Bo、Arjan W. Kleij
DOI:10.1002/anie.201504956
日期:2015.9.28
site‐selective process for the formation of N‐aryl‐carbamates from cyclic organic carbonates and aromatic amines is reported. The reactions proceed smoothly under extremely mild reaction conditions using TBD (triazabicyclodecene) as an effective and cheap organocatalyst, thus providing a sustainable and new methodology for the formation of a wide variety of useful N‐arylcarbamate synthons in good to excellent yields